Line a baking sheet with wax paper. Melt the chocolate in a heatproof bowl set over a saucepan of simmering water. Let cool for 10 minutes, stirring occasionally. Add the pretzels and stir gently until coated. Using a fork, transfer the pretzels to the wax paper, letting the excess chocolate drip back into the bowl. Refrigerate the pretzels until the chocolate is set, about 20 minutes.